PIM and RPF check problem with BGP route resolved through inet.3 and LSP

Why does PIM not use the BGP route resolved through inet.3 -> LSP as RPF next hop?Error: Upstream interface: unknown (no nexthop)BGP protocol next hop is available through IGP also (in inet.0)If I add static route to source (1.1.1.1/32) pointing at upstream interface (lt-1/2/0.10), multicast starts working.All interfaces are added to PIM and PIM neighbors are detected.

It seems RPF check is unable to use the LSP route. I did a little trick with BGP policy to avoid the LSP route to mcast source (1.1.1.1) and again the multicast started working. This is probably working as it is supposed to, it's just me not understanding why. Or maybe running pim over mpls core is something very stupid from the beginning Luckily this is in the lab...